The present invention relates to a method for preparing an ambient stable beverage, particularly a tea based beverage, that involves adding to the beverage one or more pasteurisation adjuncts that become fungicidal when activated by heat.
In recent years there has been an ever increasing choice for consumers who wish to quench their thirst with ready made beverages. Many of those are now turning from the well known soft drinks to tea based beverages, be those carbonated or still, and the xe2x80x9cnaturalxe2x80x9d refreshment they can provide.
Tea contains a complex combination of enzymes, biochemical intermediates and structural elements normally associated with plant growth and photosynthesis. There are also many natural substances that give tea its unique taste, astringency, aroma and colour. Many of these are produced by the oxidation reactions that occur during the so-called fermentation stage of black tea manufacture. Tea production has long been driven by traditional processing methods with only a fundamental understanding of the chemistry that is involved. As a consequence manufacturers have discovered making ambient stable tea based beverages at the volumes required to compete with more traditional soft drinks is not simply a matter of flavouring a soft drink with tea.
The flavour of a tea based beverage and its stability rely on the stability of the beverage as a whole. The fungi including yeasts and moulds that can grow in tea based beverages and other soft drinks can be killed by heat treatment or at least controlled by use of preservatives. Some tea based beverages are therefore pasteurised and then bottled in glass or special heat stable PET containers. This is known as xe2x80x9chot fillingxe2x80x9d. Unfortunately this can be an expensive operation that creates a great deal of environmentally unfriendly waste. It has therefore become more attractive for manufacturers to pack their tea based products in standard PET containers which can range from single serve units to multi-serve packs and maintain the stability of the product using tailor made flavour and preservative systems. This is known as xe2x80x9ccold fillingxe2x80x9d. It is also useful in that one can readily use a tea concentrate or powder.
Unfortunately the use of common preservatives can affect the flavour of a tea based beverage. This is particularly true for sulphite and sorbate. Adding a strong flavour such as lemon can offset the preservative taste. However consumers are keen to experience other flavours. Furthermore, some of those consumers that were drawn to tea based products as a more healthy and natural alternative to soft drinks sometimes view preservatives as the sort of synthetic additives they would rather avoid.
Many countries have regulations that prohibit the use of certain food additives, including some fungicides and preservatives, in foods and beverages. Regulations can vary widely but there is a clear trend for foods to contain fewer and lower levels of chemical fungicides and preservatives, particularly synthetic ones.
Accordingly there is a need for a method for preparing pleasantly flavoured ambient-stable beverages that have low levels of synthetic preservatives.
In response to that need the present inventors have now developed a fungicidal system for tea based beverages that does not contain any synthetic fungicides or preservatives. The fungicidal system can also be used to stabilise non-tea based beverages including fruit and soft drinks.
The invention can in broad terms be said to relate to a method for preparing an ambient-stable beverage suitable for cold filing comprising the steps of: adding to a beverage at least one pasteurization adjunct that has no appreciable fungicidal activity at a temperature between 0 and 40 degrees C but exhibits fungicidal activity when heated to a temperature between 40 and 65 degrees C, and raising the temperature of the beverage to a temperature between 40 and 65 degrees C in order to activate the fungicidal activity of the pasteurisation adjunct. When the beverage is tea based it preferably contains 0.01 to 3% tea solids, especially about 0.14% tea solids.
The pasteurisation adjunct is a preferably a substance that has no appreciable fungicidal activity at a temperature between 0 and 40xc2x0 C., especially between 20 and 35xc2x0 C., but exhibits fungicidal activity when heated to a temperature between 40 and 65xc2x0 C., especially between 45 and 55xc2x0 C.
Particularly preferred pasteurisation adjuncts include decyl acetate, lauric acid, lauric aldehyde, lauric alcohol, 2-dodecenal, ethyl 2-decenoate, geranyl acetone, geranyl acetate which are preferably present in a concentration no greater than 1 mM, preferably no greater than 0.1 mM.
Unlike pasteurisation-based methods for stabilising beverages, the present method is not time or temperature dependent.
xe2x80x9cBeveragexe2x80x9d for the purposes of the present invention means any drink, other than water, and includes soft drinks, fruit drinks, coffee based drinks and tea based drinks.
xe2x80x9cTeaxe2x80x9d for the purposes of the present invention means leaf material from Camellia sinensis var. sinensis or Camellia sinensis var. assamica. xe2x80x9cTeaxe2x80x9d is also intended to include the product of blending two or more of any of these teas.
For the avoidance of doubt the word xe2x80x9ccomprisingxe2x80x9d is intended to mean including but not necessarily xe2x80x9cconsisting ofxe2x80x9d or xe2x80x9ccomposed ofxe2x80x9d. In other words the listed steps or options need not be exhaustive.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or concentrations of material ought to be understood as modified by the word xe2x80x9caboutxe2x80x9d.